1. Field of the Invention
The present invention relates to a thermal printer incorporated in various kinds of portable information equipment, for performing printing by pressing a heat-generating thermal head against a recording paper.
2. Description of the Related Art
As to a thermal printer mounted to a portable information terminal or the like, for performing printing by pressing a heated thermal head against a special recording paper whose color changes when applied with heat, various models are currently on the market in large quantity. In particular, such the thermal printer is suitably used for printing various kinds of labels, receipts, tickets, and the like because the thermal printer can print characters with smooth outlines as well as multicolor graphics without using toner, ink, or the like.
In general, the thermal printer includes a thermal head having a plurality of heating elements, ahead support member for supporting the thermal head, a platen roller for nipping the recording paper with the thermal head, a motor for delivering the recording paper by rotating the platen roller through a gear, and biasing members (such as coil spring or leaf spring) for pressing the thermal head against the recording paper and the platen roller side.
In a case of performing printing, the thermal head is pressed against the recording paper while the recording paper is being delivered through rotation of the platen roller by the motor. Accordingly, the printings as described above can be performed. In recent years, there is provided a thermal printer employing a thermal line dot method, which enables a silent high-speed printing.
Incidentally, the thermal head and the recording paper are constantly in contact with each other, and during printing in particular, the thermal head and the recording paper cause friction, so electrostatic is accumulated in the thermal head. Thus, in order to let out the electrostatic, it is necessary to mount a dedicated conducting component for electric conduction. In general, a metal plate, metal coil spring, or the like has been employed as the conducting component, and one end side of the conducting component is mechanically brought into press contact with the head support member or the biasing member electrically connected with the thermal head, to thereby electrically connect the other end side thereof to a casing or a flexible substrate (i.e., circuit board for activating the thermal head or the like). Accordingly, the conducting component of the thermal head can be grounded to prevent the electrostatic from accumulating in the thermal head. Thus, the conducting component is as an essential component in a thermal printer.
However, the conventional thermal printer still has the following problems.
That is, the conducting component must be prepared only for preventing accumulation of the electrostatic in the thermal head, and assembling of the thermal printer must be performed with careful attention to the conducting component. Accordingly, production thereof requires much time and effort and costs for the conducting components have been required, thereby leading to an increase in cost and difficulty in efficient production.